The use of silicon dioxide as a replacement for carbon black in tread compounds has been known for some time. In particular, silicon dioxide is used in combination with a silane bonding agent. The silane bonding agent has the function of interacting with the silanol groups of the silicon dioxide, thus inhibiting the formation of hydrogen bonds between its particles. The formation of the above-mentioned hydrogen bonds would necessarily produce the formation of agglomerates, resulting in irregular dispersion of the silicon dioxide in the polymer base. Furthermore, the silane bonding agent, if appropriately functionalized, can interact with the polymer base to create a chemical bridge between the latter and the silicon dioxide. Compared to carbon black, silicon dioxide gives the compound improved rolling resistance and improved road holding in wet conditions.
One of the objectives of tyre research is to improve rolling resistance without deteriorating, or compromising, the other characteristics. As is known to a person skilled in the art, rolling resistance is closely linked to tyre weight. A reduction in the weight of the compound can be obtained by a reduction in the quantity of silicon dioxide. This solution, although it necessarily entails a reduction in the weight of the compound, with consequent advantages in terms of rolling resistance, nevertheless also entails a deterioration in its mechanical characteristics, for example abrasion resistance.
The need was therefore felt for a solution able to reduce the weight of the compound, without deteriorating its mechanical characteristics.
The Applicant has unexpectedly found a solution that allows reduction of the weight of the compound while maintaining unchanged, or even improving, the mechanical characteristics thereof.